What Does B1321 Mean?
This code indicates the Body Control Module (BCM) has detected a short to battery voltage in the driver door ajar switch circuit. The BCM is reading constant battery voltage on the door ajar signal wire, causing the system to register the door as always open even when closed. This occurs when the signal wire is damaged or making unintended contact with a positive voltage source.
Common Causes
45%
Damaged or chafed wiring harness in the door jamb area causing short to power
30%
Faulty driver door ajar switch with internal short to voltage
15%
Water intrusion or corrosion in door switch connector causing cross-circuit short
10%
BCM internal fault or damaged BCM connector causing false voltage reading
Diagnostic Steps
1
Step 1: Perform visual inspection of the driver door wiring harness at the hinge area and door jamb for pinched, chafed, or damaged wires. Flex the harness while observing for exposed copper or insulation damage.
2
Step 2: Disconnect the driver door ajar switch connector and measure voltage on the signal wire at the BCM side using a digital multimeter. With switch disconnected, voltage should be 0V or ground. If battery voltage is present, wiring has short to power.
3
Step 3: If no voltage at BCM with switch disconnected, measure resistance of the door ajar switch. With door closed, resistance should be high (open circuit). With door open, resistance should be low or grounded. Replace switch if readings are incorrect or if continuity to battery voltage exists.
4
Step 4: Inspect and test the BCM connector terminals for corrosion, bent pins, or signs of water intrusion. Check for proper terminal seating and integrity of connector seal.
5
Step 5: Repair or replace damaged wiring harness section, door ajar switch, or connectors as identified. Clear codes and operate door through multiple open/close cycles to verify repair and confirm code does not return.
Estimated Repair Cost
$75 - $400
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected a short to battery voltage in the driver door ajar switch circuit. The BCM is reading constant battery voltage on the door ajar signal wire, causing the system to register the door as always open even when closed. This occurs when the si...
The most common cause of B1321 (Driver Door Ajar Circuit Short To Battery) is: Damaged or chafed wiring harness in the door jamb area causing short to power
Typical repair costs for B1321 range from $75 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving. This code primarily affects interior lighting, door chime functions, and possibly security system operation. The vehicle may exhibit constant interior lights, active door chime, or false security alerts, but does not affect vehicle operation or safety.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1321 to identify the root cause.
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Quick Info
Category
Body
System
Body Control and Interior Lighting System
Difficulty
Type
Manufacturer
Recommended Tools
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